Implementation and test for horizontal rule

app/Main.hs

@@ -15,7 +15,7 @@ readLinesHelper xs = do
       readLinesHelper xs'
 
 readLines :: IO [String]
-readLines = fmap reverse $ readLinesHelper []
+readLines = reverse <$> readLinesHelper []
 
 main :: IO ()
 main = do

src/MdToHTML.hs

@@ -37,6 +37,7 @@ data MdToken
   | Codeblock String
   | Link MdToken URL
   | Image MdToken ImgPath
+  | Figure MdToken ImgPath
   | Bold MdToken
   | Italic MdToken
   | Strikethrough MdToken
@@ -59,6 +60,7 @@ instance Show MdToken where
   show (Codeblock code) = show code
   show (Link txt url) = "<a href=\"" ++ getUrl url ++ "\">" ++ show txt ++ "</a>"
   show (Image txt imgPath) = "<img src=\"" ++ getPath imgPath ++ "\"" ++ " alt=\"" ++ show txt ++ "\" />"
+  show (Figure txt imgPath) = "<figure><img src=\"" ++ getPath imgPath ++ "\" alt=\"" ++ show txt ++ "\"/><figcaption aria-hidden=\"true\">" ++ show txt ++ "</figcaption></figure>"
   show (Bold token) = "<b>" ++ show token ++ "</b>"
   show (Italic token) = "<i>" ++ show token ++ "</i>"
   show (Strikethrough token) = "<s>" ++ show token ++ "</s>"
@@ -192,7 +194,10 @@ parseLinebreak = do
 parseSingleNewline :: ReadP MdToken
 parseSingleNewline = do
   char '\n'
-  return SingleNewline
+  remaining <- look
+  case remaining of
+    [] -> return $ Unit ""
+    _ -> return SingleNewline
 
 parseImage :: ReadP MdToken
 parseImage = do
@@ -205,6 +210,13 @@ parseImage = do
   char ')'
   return $ Image (Line altText) (ImgPath path)
 
+parseFigure = do
+  img <- parseImage
+  void (string "\n\n") <++ eof
+  case img of
+    Image text path -> return $ Figure text path
+    _ -> return img
+
 -- Parse an escaped character
 parseEscapedChar :: ReadP MdToken
 parseEscapedChar = do
@@ -274,6 +286,7 @@ parsePara = do
   text <- manyTill get (string "\n\n" <|> (eof >> return ""))
   when (null text) pfail
   let parsedText = fst $ leftmostLongestParse parseLine text -- Parse a line
+  parseMany (char '\n')
   return (Para parsedText)
 
 -- Parse a line starting with '>', return the line except for the '>'.
@@ -394,12 +407,17 @@ parseOrderedList = do
   void (char '\n') <++ eof
   return $ OrdList (firstLine : lineItems)
 
+parseHorizontalRule :: ReadP MdToken
+parseHorizontalRule = string "---" *> (void (string "\n\n") <++ eof) *> return HorizontalRule
+
 documentParsers :: [ReadP MdToken]
 documentParsers =
-  [ parseHeader,
+  [ parseHorizontalRule,
+    parseHeader,
     parseBlockquote,
     parseUnorderedList,
     parseOrderedList,
+    parseFigure,
     parsePara
   ]
 

src/MdToHtmlTest.hs

@@ -102,10 +102,18 @@ codeTests =
 
 imageTests =
   TestList
-    [ check_equal "Image by itself" "<p><img src=\"img.png\" alt=\"Image 1\" /></p>" (convert "![Image 1](img.png)"),
-      check_equal "Image with text" "<p>This is an image <img src=\"img.png\" alt=\"Image 1\" /></p>" (convert "This is an image ![Image 1](img.png)")
+    [ check_equal "Image with text" "<p>This is an image <img src=\"img.png\" alt=\"Image 1\" /></p>" (convert "This is an image ![Image 1](img.png)")
     ]
 
+figureTests =
+  TestList
+    [ check_equal "Image by itself" "<figure><img src=\"img.png\" alt=\"Image 1\"/><figcaption aria-hidden=\"true\">Image 1</figcaption></figure>" (convert "![Image 1](img.png)")
+    ]
+
+horizontalRuleTests =
+  TestList
+    [check_equal "Horizontal Rule" "<p>a</p><hr><p>b</p>" (convert "a\n\n---\n\nb")]
+
 integrationTests =
   TestList
     [ check_equal "Integration 1" "<h1>Sample Markdown</h1><p>This is some basic, sample markdown.</p><h2><b>Second</b> <i>Heading</i></h2>" (convert "# Sample Markdown\n\n This is some basic, sample markdown.\n\n  ## __Second__ _Heading_"),
@@ -141,7 +149,9 @@ tests =
       unorderedListTests,
       orderedListTests,
       imageTests,
+      figureTests,
       codeTests,
+      horizontalRuleTests,
       integrationTests
     ]